Turbo Wastegate problem

[bigmikeyoyo]

Hi Guys
After blowing my second intercooler to bits I've spent the day working on the the wifes 02 1.9tdi with 155k on the clock.
Basically ever since I got a friend /mechanic to replace the first intercooler and EGR valve theres been a noise from the engine like a fluttering on changing gear. The turbo actuator is free ok but it has permanant vacuum going to it and so it is permanantly keeping the vanes closed resulting overboost and the car going into limp mode when on boost at about 3000 revs, ignition off and on again it resets itself.
Also theres no vacuum at all going to the EGR valve so its doing nothing at all. Is my n75 faulty, I cleaned the MAP sensor today and the MAF sensor so am ruling these out unless the map is done after the first intercooler blew at 90mph on the M5.
I'm inclined to say the N75 is the culprit but would like to hear any thoughts on the matter.
Thanks in advance
Mike